The associations between parity, other reproductive factors and cartilage in women aged 50-80 years

Sexual dimorphism in articular tissue anatomy - Key to understanding sex differences in osteoarthritis?

OBJECTIVE

Osteoarthritis (OA) prevalence and incidence varies between women and men, but it is unknown whether this follows sex-specific differences in systemic factors (e.g. hormones) and/or differences in pre-morbid joint anatomy. We recognize that classifications of sex within humans cannot be reduced to female/male, but given the lack of literature on non-binary individuals, this review is limited to the sexual dimorphism of articular morphotypes.

METHODS

Based on a Pubmed search using relevant terms, and input from experts, we selected articles based on the authors' judgment of their relevance, interest, originality, and scientific quality; no "hard" bibliometric measures were used to evaluate their quality or importance. Focus was on clinical rather than pre-clinical studies, with most (imaging) data being available for the knee joint.

RESULTS

After introducing "sexual dimorphism", the specific literature on articular morphotypes is reviewed, structured by: radiographic joint space width (JSW), meniscus, ligaments, articular cartilage morphology, articular cartilage composition and deformation, and articular tissue response to treatment.

CONCLUSIONS

Sex-specific differences were clearly observed for JSW, meniscus damage, ligament size, and cartilage morphometry (volume, thickness, and surface areas) but not for cartilage composition. Ligament and cartilage measures were smaller in women even after matching for confounders. Taken together, the findings indicate that female (knee) joints may be structurally more vulnerable and at greater risk of OA. The "one size/sex fits all" approach must be abandoned in OA research, and all observational and interventional studies should report their results for sex-specific strata, at least in pre-specified secondary or post-hoc analyses.

Impact of parity on biomechanical risk factors for knee OA initiation

BACKGROUND

Women are twice as likely as men to develop knee osteoarthritis (OA), and with it experience greater losses of physical function and disability. A change in the mechanical environment of the joint is a key initiating factor for knee OA. Differences in morphology, joint injury risk, and hormonal shifts in mid-life are often considered factors which increase OA risk for women. Pregnancy, a time of significant hormonal, morphological, and biomechanical change, has received comparably less attention. If morphological and biomechanical changes persist postpartum, this could increase OA risk for parous (childbearing) women.

RESEARCH QUESTION

Are lower limb gait mechanics different between healthy nulliparous (non-childbearing) and parous (childbearing) women?

METHODS

Twenty-eight self-reported not pregnant female participants (14 parous, 14 nulliparous) were recruited for the study. Nulliparous participants had never given birth to a child. Parous participants had given birth to at least one full-term infant (37-42 weeks) without complications between one to five years before data collection. Motion capture of participants' preferred, fast, and set (1.4 m/s) walking speeds was conducted. Repeated measures ANOVA were performed to test for significant group differences in joint kinematics and kinetics.

RESULTS

There was a significant main effect of group indicating a larger knee flexion angle at toe off (p = 0.0002), smaller knee extension moment at heel strike (p = 0.0006), smaller first peak knee flexion moment (p = 0.040), and smaller peak hip adduction moment for the parous group compared to the nulliparous group (p = 0.003). Static Q-angle did not differ between groups.

SIGNIFICANCE

Alteration in mechanics from the habitual loading pattern are thought to increase risk of OA. Smaller knee moments in post-partum women could alter the mechanical stimulus to cartilage, and should be investigated in conjunction with cartilage health measures to determine the link with OA initiation.

Abortion is associated with knee osteoarthritis among older women in China: A STROBE-compliant article

The current studies revealed inconsistent relationship between reproductive factors and osteoarthritis. Community-based research has not been conducted in China. The study was to examine the association of reproductive factors with the prevalence of knee osteoarthritis (OA).Through a multistage stratified random sampling method, 10 streets or villages from 5 cities in Hunan province were randomly selected, a total 2746 eligible women aged 50 to 83 were recruited in this cross-sectional study. A structured questionnaire including demographic factors, socio-economic status, reproductive factors, and knee OA was used. According to the criteria of American College of Rheumatology, clinical knee OA was assessed by doctors in community or village health clinics for knee pain, age, morning stiffness, crepitus on active motion or for knee pain, morning stiffness, crepitus on active motion, and tenderness of the bony navigation of the joint. Self-reported age of menarche, parity, abortion history, and menopausal status were collected.The prevalence of knee OA was 13.44%. Abortion is associated with knee OA (odds ratio [OR] = 1.271, 95% confidence interval [CI] = 1.007, 1.606), but age at menarche, parity, and menopausal status were not the factors. Furthermore, age (OR = 1.040, 95% CI = 1.020, 1.060), weight (OR = 1.019, 95% CI = 1.004, 1.035), higher education level (OR = 1.530, 95% CI = 1.121, 2.088), higher monthly household income (OR = .583, 95% CI = 0.441, 0.770 for 3000-4999 ¥ and OR = 0.599, 95% CI = 0.431, 0.833 for 5000 ¥ or more), and chronic gastritis (OR = 3.364, 95% CI = 2.548, 4.442) were associated with knee OA.Abortion may increase the risk of knee OA. Special attention should be paid to women with a history of abortion, and women who are planning to abort should be informed of the risk of knee OA later in life. The relationship between abortion and knee OA should be interpreted with caution and further confirmed.

Reproductive history and osteoarthritis in the Women's Health Initiative

Objective: To investigate the relationship between self-reported osteoarthritis (OA) and reproductive factors in the Women's Health Initiative (WHI). Method: We used multivariable logistic regression to study the association of self-reported OA and reproductive factors in the WHI Observational Study and Clinical Trial cohorts of 145 965 postmenopausal women, in a retrospective cross-sectional format. Results: In our cohort, we observed no clinically significant associations between reproductive factors and OA given small effect sizes. The following factors were associated with statistically significant increased likelihood of developing OA: younger age at menarche (p < 0.001), history of hysterectomy [adjusted odds ratio (aOR) 1.013, 95% confidence interval (CI) 1.004-1.022, p = 0.04 vs no hysterectomy], history of unilateral oophorectomy (aOR 1.015, 95% CI 1.004-1.026, p < 0.01 vs no oophorectomy), parity (aOR 1.017, 95% CI 1.009-1.026, p < 0.001), ever use of oral contraceptives (aOR 1.008, 95% CI 1.001-1.016, p < 0.01 vs never use), and current use of hormonal therapy (reference current users, aOR 0.951, 95% CI 0.943-0.959 for never users; aOR 0.981, 95% CI 0.972-0.989 for past users; global p < 0.001). Age at menopause, first birth, and pregnancy were not associated with OA. Among parous women, no clear pattern was observed with number of pregnancies, births, or duration of breastfeeding in relation to OA. Conclusion: Our study showed that reproductive factors did not have significant clinical associations with OA after controlling for confounders. This may be due to complex hormonal effects. Additional investigation is warranted in prospective cohort studies. The Women's Health Initiative is registered under ClinicalTrials.gov. Trial registration ID: NCT00000611.

Reproductive factors and risk of total knee replacement due to severe knee osteoarthritis in women, the Singapore Chinese Health Study

OBJECTIVES

Knee osteoarthritis (OA) is more common in women, and may be related to reproductive or hormonal factors. We evaluated these factors with the risk of total knee replacement (TKR) for severe knee OA among women.

METHODS

The Singapore Chinese Health Study recruited 63,257 Chinese aged 45-74 years from 1993 to 1998, and among them, 35,298 were women. Information on height, weight, lifestyle factors, number of biological children, ages at menarche and menopause, and use of hormonal therapies was collected through interviews. Incident cases of TKR were identified via linkage with nationwide database.

RESULTS

There were 1,645 women with TKR after mean follow-up of 14.8 years. Higher parity was associated with increased TKR risk in a stepwise manner (P for trend <0.001). Compared to nulliparous women, those with ≥5 children had the highest risk [hazard ratio (HR) 2.01, 95% confidence intervals (CIs) 1.50-2.70]. The effect of parity on TKR risk was significantly stronger among lean women compared to heavier women; HRs (95% CIs) for highest parity was 4.86 (2.22-10.63) for women with body mass index (BMI) <23 kg/m² and 1.57 (1.14-2.14) for those ≥23 kg/m² (P for interaction = 0.001). Earlier age at menarche and use of oral contraceptives were significantly associated with TKR in a stepwise manner (P for trend ≤0.002). Age at menopause and use of hormonal therapy were not associated with TKR risk.

CONCLUSION

Higher parity, earlier age of menarche and use of oral contraceptives were associated with increased risk of TKR for severe knee OA among women.

Pregnancy Results in Lasting Changes in Knee Joint Laxity

BACKGROUND

Altered joint laxity can contribute to joint dysfunction. Knee joint laxity has been shown to increase during pregnancy, but its long-term persistence is unknown.

OBJECTIVE

To determine whether pregnancy leads to lasting increases in knee joint compliance and laxity that persist longer than 4 months postpartum.

DESIGN

Prospective cohort study.

SETTING

A motion analysis laboratory at an academic medical center.

PARTICIPANTS

Fifty healthy women in their first trimester of pregnancy (mean ± SD 29.2 ± 4.3 years old and baseline body mass index 26.0 ± 5.4 kg/m² ) were recruited.

INTERVENTION

End-range knee laxity and midrange joint compliance were measured during the first trimester and 19 ± 4 weeks postpartum. Anterior-posterior and varus-valgus laxity were measured using 3-dimensional motion tracking while applying forces and moments in each respective plane using the Vermont Knee Laxity Device. Nonlinear models were constructed to assess relations between applied forces and joint translation, comparing early pregnancy with postpartum.

OUTCOMES

Multiplanar knee laxity and compliance.

RESULTS

Peak varus-valgus (20-22%; P = .001) and posterior translation (51%; P < .001) of the tibia relative to the femur decreased from baseline, with a concomitant decrease in laxity (P < .001) and compliance (P = .039) in the coronal plane and in the posterior direction in primiparous (P = .009) and multiparous (P = .014) women. For primiparous women, laxity (P < .001) and compliance (P = .009) increased in the anterior direction.

CONCLUSIONS

Pregnancy resulted in a lasting decrease in multiplanar knee laxity and compliance in the varus and posterior directions with an increase in anterior compliance. The effects of these changes in laxity and compliance of the passive stabilizers on knee loading patterns, articular contact stresses, and risk for osteoarthritis and other musculoskeletal disorders will require additional research.

LEVEL OF EVIDENCE

II.

Female Reproductive and Hormonal Factors and Incidence of Primary Total Knee Arthroplasty Due to Osteoarthritis

OBJECTIVE

To examine the associations of female reproductive and hormonal factors with incidence of total knee arthroplasty (TKA) for osteoarthritis (OA), and to determine whether the associations differ according to overweight/obesity status.

METHODS

This study included 22,289 women in the Melbourne Collaborative Cohort Study. Data on age at menarche, pregnancy, parity, years of menstruation, oral contraceptive (OC) use, menopausal status, and hormone replacement therapy (HRT) were collected in 1990-1994. Incidence of TKA during 2001-2013 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry. All analyses were adjusted for age, body mass index (BMI) at midlife, change in BMI (from early reproductive age to midlife), country of birth, physical activity, smoking, and education level.

RESULTS

Over the course of 12.7 years, 1,208 TKAs for OA were identified. Ever being pregnant was associated with increased risk of TKA (hazard ratio [HR] 1.32 [95% confidence interval (95% CI) 1.06-1.63]). Parity was positively associated with risk of TKA (P for trend = 0.003). OC users had increased risk of TKA compared with non-users (for OC use of <5 years, HR 1.25 [95% CI 1.08-1.45]; for OC use of ≥5 years, HR 1.17 [95% CI 1.00-1.37]). A 1-year increase in menstruation was associated with a 1% decrease in risk of TKA (HR 0.99 [95% CI 0.97-0.99]). These associations remained significant only in women of normal weight at early reproductive age. Current HRT users had increased risk of TKA compared with non-users (HR 1.37 [95% CI 1.14-1.64]); the association was significant only in non-obese women at midlife.

CONCLUSION

Reproductive and hormonal factors were associated with risk of knee OA. These associations remained significant in women of normal weight at early reproductive age and in non-obese women at midlife. Further work is needed to understand the complex effect of these factors on knee OA.

Female hormonal factors and osteoarthritis of the knee, hip and hand: a narrative review

Osteoarthritis is a leading cause of disability with no cure. The incidence of osteoarthritis is sexually dimorphic: women have a higher rate of osteoarthritis than men after the age of 50. Research has investigated the contribution of sex hormones, reproductive factors and hormone supplementation to osteoarthritis. It has been recognized that different joints are susceptible to different risk factors for osteoarthritis. We reviewed the evidence for the effect of endogenous sex hormones, reproductive factors and hormone supplementation on joint-specific osteoarthritis of the knee, hip and hand. Although the role of these hormonal factors in the pathogenesis of osteoarthritis is complex, data suggest that endogenous hormones and reproductive factors have a role in the pathogenesis of osteoarthritis, especially knee osteoarthritis, with uncertainty for the effect of exogenous hormones. From the available data, it is hard to conclude whether this is a direct effect of hormonal factors, or whether other factors related to these hormonal factors, i.e. obesity and inflammation, have a role in this association. Further studies should consider the mediation effect of body weight and inflammation, change in body weight throughout life, circulatory levels of all endogenous hormones and circulatory levels of hormones after hormone supplementation in this complex relationship.

Age of menarche is associated with knee joint replacement due to primary osteoarthritis (The HUNT Study and the Norwegian Arthroplasty Register)

OBJECTIVE

To investigate whether parity, age at menarche, menopausal status, age at menopause, use of oral contraceptives (OC) or use of hormone replacement therapy (HRT) were associated with total knee replacement (TKR) or total hip replacement (THR) due to primary osteoarthritis.

METHOD

In a prospective cohort study of 30,289 women from the second and third surveys of the Nord-Trøndelag Health Study, data were linked to the Norwegian Arthroplasty Register (NAR) in order to identify TKR or THR due to primary osteoarthritis. Cox proportional hazards models were used to estimate the hazard ratios (HRs).

RESULTS

We observed 430 TKRs and 675 THRs during a mean follow-up time of 8.3 years. Increasing age at menarche was inversely associated with the risk of TKR (P-trend < 0.001). Past users and users of systemic HRT were at higher risk of TKR compared to never users (HR 1.42 (95% confidence interval (CI) 1.06-1.90) and HR 1.40 (95% CI 1.03-1.90), respectively). No association was found between parity, age at menarche, menopausal status, age at menopause, oral contraceptive use or HRT use and THR.

CONCLUSION

We found that increasing age at menarche reduced the risk of TKR. Past users and users of systemic HRT were at higher risk of TKR compared to never users. Parity did not increase the risk of THR or TKR.

Parity and risk of ovarian cysts: Cross-sectional evidence from the Dongfeng-Tongji cohort study

Little is known about the association between parity and the risk of ovarian cysts. The aim of this study was to examine the association between parity and the risk of ovarian cysts among a population of Chinese women. A total of 20 502 women aged 45-86 years from the Dongfeng-Tongji Cohort study completed baseline questionnaires, medical examination and provided baseline blood samples. Participants were categorized into four groups according to parity (one, two, three, and four or more live births). Logistic regression models were used to investigate the association between parity and the risk of ovarian cysts. The prevalence of ovarian cysts in the study population was 4.0% (816/20 502). Increasing parity was associated with decreasing risk of ovarian cysts without adjustment for any covariates and after age-adjusted model (P<0.001). After adjusting for potential confounders, women who had had four or more live births had lower risk of ovarian cysts (OR: 0.51; 95% CI: 0.27-0.96) compared with women who had had one live birth. There was a consistent but non-significant decreased risk of ovarian cysts for women who had had two, and three live births (OR: 0.85; 95% CI: 0.68-1.05) and (OR: 0.84; 95% CI: 0.59-1.20) respectively compared with women who had had one live birth. It was concluded that higher parity was associated with decreasing risk of ovarian cysts in this population of Chinese women. These findings could be helpful in decision making in clinical practice for gynecologists when evaluating women suspected to have ovarian cysts.

Aromatase expression in human chondrocytes: An induction due to culture

OBJECTIVES

Despite the high prevalence of osteoarthritis (OA) in postmenopausal women, a relationship between circulating estrogen levels and the development of OA has not been found. Therefore, the purpose of this study was to evaluate the expression and activity of aromatase, a key enzyme in local production of estrogens, in human OA cultured articular chondrocytes, and to determine the physiological relevance of this enzyme in cartilage.

METHODS

Human OA articular chondrocytes were isolated and cultured. Local production of estradiol was measured after incubation with 100 ng/ml testosterone for 8 and 24h. Furthermore, chondrocytes were culture for 2h, 48 h, 7 days or 15 days, or in alginate beads for 10 days. Aromatase, type II and X collagen, aggrecan, alkaline phosphatase, and Runx2 expression were evaluated in cartilage, freshly isolated chondrocytes and cultured chondrocytes.

RESULTS

Aromatase was expressed and active in cultured human chondrocytes. Human cartilage, freshly isolated chondrocytes, and chondrocytes cultured for 2h expressed an insignificant amount of aromatase; however, expression arose after 48 h of culture and remained increased thereafter. Aromatase expression was not related to estrogen deprivation and was inversely correlated with differentiation. Re-differentiation did not reduce its expression.

CONCLUSIONS

Aromatase presents an almost undetectable expression in human cartilage but is induced in cultured chondrocytes. Therefore, human cartilage might act as a mere target for estrogens rather than a producer, and researchers using cell expansion in culture for latter therapies should consider these changes in estrogen metabolism which may not be reverted after re-differentiation.

The role of imaging in osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disorder with no approved disease-modifying treatment available. The importance of imaging in assessing all joint structures involved in the disease process, including articular cartilage, meniscus, subarticular bone marrow, and synovium for diagnosis, prognostication, and follow-up, has been well recognized. In daily clinical practice, conventional radiography is still the most commonly used imaging technique for the evaluation of a patient with known or suspected OA and radiographic outcome measures are still the only approved end point by regulatory authorities in clinical trials. The ability of magnetic resonance imaging (MRI) to visualize all joint structures in three-dimensional fashion including tissue ultrastructure has markedly deepened our understanding of the natural history of the disease. This article describes the roles and limitations of different imaging modalities for clinical practice and research in OA, with a focus on radiography and MRI and an emphasis on the knee joint.

The association of parity with osteoarthritis and knee replacement in the multicenter osteoarthritis study

OBJECTIVE

We evaluated the association of parity to both risk of knee replacement (KR) and knee osteoarthritis (OA).

DESIGN

The NIH-funded Multicenter Osteoarthritis Study (MOST) is a longitudinal observational study of persons age 50-79 years with either symptomatic knee OA or at elevated risk of disease. Baseline and 30-month knee radiographic OA (ROA) was defined as Kellgren/Lawrence (K/L) grade ≥2 or KR. Women were grouped based by number of births: 0; 1 (reference group); 2; 3; 4; and 5 or more. We examined the relation of parity to the incidence over 30 months of ROA and KR using a Poisson regression model. Generalized estimating equations (GEE) were used to control for correlation between two knees within a subject. We adjusted for age, BMI, race, education, occupation, baseline estrogen use, clinical site, injury, and for KR analyses WOMAC pain and use of pain medication.

RESULTS

Among 1618 women who reported parity information, mean age was 62.6 years, mean BMI 30.7 kg/m(2), mean WOMAC pain subscale score 3.7 at baseline. There were 115 KRs and 134 cases of incident knee ROA over 30 months. The relative risk of incident KR was 2.7 times as high (95% CI: 1.0, 7.3) and relative risk of incident knee ROA was 2.6 times as high (95% CI: 1.2, 5.3) among women with five to 12 children compared with those with one birth.

CONCLUSION

Parity in women at risk for OA is associated with both incident ROA and KR, particularly for those with more than four children.

Osteoarthritis year 2012 in review: imaging

PURPOSE

This article reviews original publications related to imaging in osteoarthritis (OA) published in English from September 2011 through March 2012. In vitro data and animal studies are not covered.

METHODS

To extract relevant studies, an extensive PubMed database search was performed using the query terms "osteoarthritis" in combination with "MRI", "imaging", "radiography", "ultrasound", "computed tomography" and "nuclear medicine". Publications were sorted according to relevance based on potential impact to the OA research community with the over all goal of a balanced overview of all aspects of imaging. Focus was on publications in high-impact special-interest journals. The literature will be presented by topics covering radiography, morphologic magnetic resonance imaging (MRI), compositional and high-field MRI, quantitative MRI, ultrasound, other joints and systematic reviews. Original research that was presented as a podium or poster presentation at osteoarthritis research society international (OARSI) 2012 will not be included.

RESULTS AND CONCLUSIONS

For the search topics "MRI" and "osteoarthritis" a decrease in overall publications was observed over the 6 months following September 2011 when compared to the previous 6 months (-38.1%). For the terms "radiography" and "osteoarthritis" a decrease of 56.9% was noted. The 6 months since the last OARSI conference were characterized by several MRI-based studies dealing with epidemiologic and methodologic aspects of disease. Other modalities such as radiography or ultrasound received much less attention. Most imaging research is still concentrated on the knee although interest in other sites, especially the hand, has increased since the last OARSI meeting.

The association between parity and knee cartilage in young women

OBJECTIVES

There have been no reported studies of the association between parity and cartilage in young individuals. The aim of this study was to describe the association between parity, cartilage volume and cartilage defects in women aged 31-41 years.

METHODS

Cross-sectional study of 144 women, mean age 36 years and BMI 25 kg/m(2), who were participants in an established prospective study. Parity was assessed using a questionnaire. Knee (medial tibial, lateral tibial and patellar) cartilage volume, cartilage defects (grade 0-4 depending on the severity of cartilage thickness loss at tibial and patellar sites) and tibial bone area were assessed using T1-weighted fat-suppressed MRI.

RESULTS

The prevalence of cartilage defects (grade ≥2) in this population was 13%. Parity was associated with a higher risk of cartilage defects at the patellar [prevalence ratio (PR) per birth 1.52, 95% CI 1.05, 2.21; PR parous vs nulliparous 1.93, 95% CI 0.66, 5.65], but not tibial sites, after adjustment for confounders including age, BMI, smoking, physical activity, knee injury and tibial bone area. This association between parity and patellar cartilage defects was stronger for those women who had three or more births (vs nulliparous, PR 5.27, 95% CI 1.39, 20.01). There were no significant associations between parity and cartilage volume.

CONCLUSION

Parity was associated with knee cartilage defects primarily at the patellar site in this sample of young women. This association was more apparent with increasing number of live births, suggesting a possible adverse effect of parity on knee cartilage.

Osteoarthritis year 2011 in review: imaging in OA--a radiologists' perspective

With major technological advances and application of magnetic resonance imaging (MRI) to large longitudinal osteoarthritis (OA) studies the role of imaging has become increasingly important for OA research over the last years. Currently, radiography, MRI and ultrasound are the most established imaging tools applied in a research setting. MRI assessment of OA features can be morphologic, compositional and can be applied in non-loaded and loaded conditions. Morphologic assessment includes semiquantitative and quantitative analyses. Novel semiquantitative scoring methods for knee, hip and hand OA using MRI were introduced. A series of key reports were published this year, reviewing the importance of radiography and MRI as a research tool. Although radiography is insensitive for the detection of OA-related structural pathology when compared to MRI, it still has been widely used for subject inclusion in observational and interventional studies due also to a straight forward disease definition that was established more than 50 years ago. In an attempt to generate an MRI-based definition of structural disease, a Delphi exercise was performed to develop a testable MRI definition of structural OA. This presentation reviews publications related to imaging of OA, published in English between September 2010 and October 2011, excluding animal studies or in vitro data. This is not a systematic or comprehensive review and the selection of papers included is based on the expert opinions of the presenter, from a musculoskeletal radiologist's perspective.